Write heads with floating side shields and manufacturing methods

ABSTRACT

A write head for a media drive suited for perpendicularly recording data in adjacent magnetic recording media, the media having a magnetic recording layer and a soft underlayer (SUL). The write head has a pole tip, a write yoke connected to the pole tip, a write return yoke, a write shield, one or more conductive coils surrounding the write yoke, and one or more side shields disposed in close proximity to the pole tip. The write return yoke connects to the write yoke on one end and the write shield on a different end. The one or more side shields are separated from the pole tip and write shields by a non-magnetic material and therefore are “floating” and not directly coupled to the write shield or pole tip.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is an application claiming the benefit under 35 USC119(e) from U.S. Provisional Application Ser. No. 60/697,582, filed Jul.8, 2005, entitled “Floating Side Shields for Write Heads”, the contentsof which are incorporated by reference herein. This application is alsoan application claiming the benefit under 35 USC 119(e) from U.S.Provisional Application Ser. No. 60/709,578, filed Aug. 19, 2005,entitled “Floating Side Shields for Write Heads”, the contents of whichare incorporated by reference herein.

BACKGROUND

1. Field of the Invention

The present invention relates generally to media write heads having atleast one floating side shield and, in particular embodiments, to diskdrive write heads with floating side shields that reduce fringe fieldeffects on neighboring tracks during the performance of a writeoperation, and methods to manufacture such write heads.

2. Related Art

Disk drives are used in a variety of electronic devices, ranging frompersonal computers to portable media players, for the storage andretrieval of data. In a disk drive, data is typically written to andread from magnetic storage media called disks. A disk drive typicallycomprises a plurality of disks for the storage of data and one or moreread/write heads for the reading and writing of data. There is aconstant market demand to increase the data storage density of disks.Increasing the storage density of the disks can decrease the price tostorage-capacity ratio of the disk drives, increase performance, anddecrease the physical dimensions of the disk drive.

The write head typically comprises a pole tip, a yoke supporting thewrite pole tip, and conductive coils around the yoke for electricallymagnetizing the write pole tip. During a write operation where the diskdrive changes the storage state of a bit of data on the disk, the writehead is moved to the location of the bit of data such that the pole tipis positioned directly above the bit, an electric current is passedthrough the coils to magnetize the pole tip, which in turn causes themagnetization of the bit to change.

In recent years, perpendicular recording has been introduced to achievegreater data storage density for disk drives. In perpendicularrecording, the magnetization of each bit is aligned vertically,perpendicular to the disk surface. Compared to longitudinal recording, aperpendicular recording system allows more data bits per unit of disksurface area, which in turn enables greater data storage density for thedisk drives.

On the surface of a disk, the data bits are arranged in concentriccircles called tracks. As the area needed for each bit decreases, thetrack width also decreases, thus increasing the number of tracks perinch and the storage density of the disk. However, as the tracks becomemore closely spaced, a problem arises when the fringe magnetic fieldemitted by the write pole tip during a write operation affects themagnetic storage state of bits on a neighboring track. The fringe fieldcan cause inadvertent erasures on neighboring tracks, or enhance thermaldecay of adjacent tracks. These effects could cause data loss, adecrease in data storage reliability, or catastrophic failures to thedisk drive.

In light of the problem discussed above, it is therefore preferable tohave a write head design that reduces the fringe fields emitted by thewrite pole tip. One method of producing such a write head is proposed byU.S. Pat. No. 4,935,832, which discloses side shields connected to adownstream pole of the write head for the reduction of fringe fieldsemitted from the write pole tip.

The side shield design disclosed in U.S. Pat. No. 4,935,832 is difficultto manufacture due to the difficulty in controlling the gap distancebetween the side shields and the write pole tip, in addition to the needto define the gap distance between the write pole tip and the writeshield (return shield). Since the write pole tip and the write shield(to which the side shields are attached to) are manufactured in separatesteps, it is impractical to accurately define the gap distances betweenthe write pole tip, write shield, and side shields using the currentmanufacturing techniques.

In addition, the structure disclosed in U.S. Pat. No. 4,935,832 hasanother disadvantage of creating magnetic flux leakage from the writepole tip. During a write operation, the write pole tip is highlymagnetized and thus have a relatively high magnetic potential (V_WP).The magnetic potential of the write shield (return shield) is usually ata very low value creating a return path for the magnetic flux. Since theside shields and the write shield are connected, the side shields havesubstantially similar magnetic potentials as the very low magneticpotential of the write shield. Hence, there is likely a leakage ofmagnetic flux from the write pole tip to the side shields. Thisside-shield leakage is proportional to the difference between thepotential of the write pole tip (V_WP) and the potential of the sideshields (V_SS). During a write operation, this potential differencebetween V_WP and V_SS can be large, causing a large amount of magneticflux leakage from the write pole tip to the side shields. This fluxleakage decreases the overall efficiency of the write head because morecurrent is needed to induce sufficient magnetic field to achieve thewrite operation. The side-shield leakage is also inversely proportionalto the gap distance between the side shield and the write pole tip.Thus, increasing the gap distance between the side shield and the writepole tip can reduce side-shield leakage. However, if this gap distanceis larger than the track-to-track pitch of the disk, the side shieldwill cease to protect adjacent tracks from fringe field effects.Therefore, using a design in which the side shields are connected to andmagnetically coupled with the write shield, magnetic flux leakage fromthe write pole tip to the side shields is likely unavoidable.

Therefore, embodiments of the present invention relate to creating awrite pole tip with side shields which reduces fringe field effects onadjacent tracks but also reduces side-shield leakage, utilizing amanufacturing process easily controllable with the current manufacturingtechniques.

SUMMARY OF THE DISCLOSURE

Embodiments of the present invention relate generally to disk drivewrite heads with one or more floating side shields that shield adjacenttracks of the disk from fringe field effects, and methods to manufacturesuch write heads.

A write head according to a general embodiment of the present inventionis suited for perpendicularly recording data in adjacent magneticrecording media, said media comprising a magnetic recording layer and asoft underlayer (SUL). The write head comprises a pole tip, a write yokeconnected to the pole tip, a write return yoke, a write shield, one ormore conductive coils surrounding the write yoke, and one or more sideshields disposed in close proximity to the pole tip. The write returnyoke connects to the write yoke on one end and the write shield on adifferent end. The one or more side shields are separated from the poletip and write shields by a non-magnetic material. Hence, in this generalembodiment, the side shields are “floating” and not directlymagnetically coupled with the write shield or pole tip.

In various embodiments, the one or more side shields comprises two sideshields disposed in parallel to the write shield, and on opposite sidesof the pole tip. In some embodiments, the two side shields are separatedfrom the pole tip by an equal gap distance.

In various embodiments, the one or more side shields are encased innon-magnetic material.

In various embodiments, the magnetic potential of each of the one ormore side shields is higher than the magnetic potential of the writeshield during a write operation.

In various embodiments, the one or more side shields are dimensioned andspaced such that each of the one or more side shields has a magneticpotential higher than a magnetic potential of the write shield but aninduced field in the media from each of the one or more side shields islower than the nucleation field of the magnetic recording layer during awrite operation.

In various embodiments, the height of each side shield is longer thanthe neck length of the pole tip. The height of the side shield ismeasured along the edge of the side shield substantially parallel to andin closest proximity to the pole tip.

In various embodiments, the gap distance between the pole tip and sideshields is between 10% to 40% of a track pitch of the magnetic recordinglayer, and the gap distance is also larger than 50% of the pole tip tosoft underlayer (SUL) distance during a write operation. The track pitchis measured by the distance from the middle of one track to the middleof its immediate neighboring track.

In various embodiments, the side shields are dimensioned and spaced suchthat the magnetic flux leakage from the pole tip to the side shieldsaccount for less than 20% of the total magnetic flux flowing through thepole tip, during a write operation.

In various embodiments, each side shield is connected to the writeshield by a magnetic connector, wherein the cross-sectional width ofeach magnetic connector is less than the width of the side shield. Thewidth of the side shield is measured by the edge of the side shieldsubstantially parallel to and closest to the write shield.

In various alternate embodiments, instead of a non-magnetic materialseparating each of the one or more side shields from the write shield,the material separating each side shield from the write shield may bemagnetic with low saturation magnetization or low permeability. In suchembodiments, a potential of each side shield may still be higher than apotential of the write shield. Also, in some alternate embodiments, thematerial separating each of the one or more side shields from the writeshield may be magnetic with low saturation magnetization or lowpermeability such that a drop of magnetic potential from the writeshield to each side shield is at least 25% of a potential differencefrom the write shield to the SUL of the magnetic recording media.

Moreover, in various alternate embodiments, instead of a non-magneticmaterial separating each of the one or more side shields from the poletip, the material separating each side shield from the pole tip may bemagnetic with low saturation magnetization or low permeability. In somealternate embodiments, a material separating each side shield from thepole tip may be magnetic with low saturation magnetization or lowpermeability and a particular material separating each side shield fromthe write shield may be magnetic with low saturation magnetization orlow permeability. For various such alternate embodiments, low saturationmagnetization and low permeability limits for a suitable magneticmaterial to separate the one or more side shields from the pole tip maybe different than low saturation magnetization and low permeabilitylimits for a suitable particular magnetic material to separate the oneor more side shields from the write shield.

A disk drive device according to an embodiment of the present inventioncomprises one or more recording medium and one or more magnetic headsupported for perpendicular recording on the one or more recordingmedium. Each recording medium comprising a soft underlayer (SUL)supporting a magnetic recording layer. Each magnetic head comprises apole tip, a write yoke connected to the pole tip, a write return yoke, awrite shield, one or more electrically conductive coils surrounding thewrite yoke, and one or more side shields disposed in close proximity tothe pole tip. The write return yoke connects to the write yoke on oneend and the write shield on a different end. Each side shield isseparated from the pole tip and write shield by a non-magnetic material.In various alternate embodiments, instead of a non-magnetic materialseparating each side shield from the write shield, the materialseparating each side shield from the write shield may be magnetic withlow saturation magnetization or low permeability.

A method for manufacturing a magnetic head for a disk drive according toan embodiment of the present invention comprises the steps of depositinga first non-magnetic spacer layer, depositing a plating seed layer,plating at least one side shield and a pole tip layer on the firstnon-magnetic spacer layer, depositing a layer of a first non-magneticmaterial using ion-beam assisted deposition, and planarizing using achemical-mechanical polishing step. The side shields and the pole tiplayer are defined by a common mask, and are separated by a trench.

In various embodiments, the ion-beam assisted deposition is a normalincident ion-beam assisted deposition, and the trench between the sideshields and the pole tip is completely filled by said deposition.

In various other embodiments, the ion-beam assisted deposition is anangled-incident ion-beam assisted deposition, and the method ofmanufacturing the magnetic head further comprises the step of fillingtrench between the side shields and the pole tip using anelectro-plating process. In one embodiment, the angled-incident ion-beamassisted deposition is processed using a +/−20 degree angle. In anotherembodiment, the method of manufacturing the magnetic head furthercomprises a step of a normal-incident ion milling to expose the platingseed layer on the bottom of the trench between the at least one sideshield and the pole tip, said step of the ion milling occurringsubsequent to the step of the angled-incident ion-beam assisteddeposition and before the step of electro-plating.

In various other embodiments, the method of manufacturing the magnetichead further comprises the steps of depositing a write yoke layer on thepole tip layer, said write yoke layer covering the pole tip layer exceptin a pole tip region; depositing a second non-magnetic spacer layeruniformly over the pole tip layer and write yoke layer; depositing anon-magnetic ramp on the second non-magnetic spacer layer encasingconductive coils; and, depositing a magnetic layer on the nonmagneticramp and second non-magnetic spacer layer to form a write shield andwrite return yoke.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a simplified top view of a disk drive;

FIG. 2 illustrates a typical read/write head;

FIG. 3 illustrates the pole tip region of a typical write head, FIG. 3(a) illustrates a frontal view, and FIG. 3( b) illustrates a bottom (ABS)view;

FIG. 4 illustrates the pole tip region of a write head with side shieldsconnected to the write shield, FIG. 4( a) illustrates a frontal view,and FIG. 4( b) illustrates a bottom (ABS) view;

FIG. 5 illustrates the pole tip region of a write head with floatingside shields according to one embodiment of the present invention, FIG.5( a) illustrates a frontal view, and FIG. 5( b) illustrates a bottom(ABS) view;

FIG. 6 illustrates the pole tip region of a write head according toanother embodiment of the present invention, FIG. 6( a) illustrates afrontal view, and FIG. 6( b) illustrates a bottom (ABS) view;

FIG. 7 illustrates the pole tip region of a write head according to yetanother embodiment of the present invention, FIG. 7( a) illustrates afrontal view, and FIG. 7( b) illustrates a bottom (ABS) view;

FIGS. 8( a) and 8(b) illustrate the processing steps for one method ofdepositing non-magnetic material between the side shields and thepole-tip;

FIGS. 9( a), 9(b), and 9(c) illustrate a method of depositingnon-magnetic material between the side shields and the pole-tipaccording to an embodiment of the present invention;

FIGS. 10( a)-(e) illustrate another method of depositing non-magneticmaterial between the side shields and the pole-tip according to anotherembodiment of the present invention;

FIG. 11 illustrates a process layers near the pole tip region of a poletip according to an embodiment of the present invention.

DETAILED DESCRIPTION

Reference will now be made to the accompanying drawings, which assist inillustrating the various pertinent features of the present invention.Although the present invention will now be described primarily inconjunction with disk drives, it should be expressly understood that thepresent invention may be applicable to other applications where magneticrecording of data is required/desired. In this regard, the followingdescription of a disk drive is presented for purposes of illustrationand description. Furthermore, the description is not intended to limitthe invention to the form disclosed herein. Consequently, variations andmodifications commensurate with the following teachings, and skill andknowledge of the relevant art, are within the scope of the presentinvention. The embodiments described herein are further intended toexplain best modes known of practicing the invention and to enableothers skilled in the art to utilize the invention in such, or otherembodiments and with various modifications required by the particularapplication(s) or use(s) of the present invention.

Embodiments of the present invention relates to write head designs whichutilizes a floating side shield to reduce or eliminate magnetic fringefields emitted by the pole tip. Such a write head is used in theread/write head of a disk drive 10.

FIG. 1 illustrates one embodiment of a disk drive 10. The disk drive 10generally includes a base plate 12 and a cover (not shown) that may bedisposed on the base plate 12 to define an enclosed housing or space forthe various disk drive components. The disk drive 10 includes one ormore data storage disks 14 of any appropriate computer-readable datastorage media. Typically, both of the major surfaces of each datastorage disk 14 include a plurality of concentrically disposed tracksfor data storage purposes. Each disk 14 is mounted on a hub or spindle16, which in turn is rotatably interconnected with the disk drive baseplate 12 and/or cover. Multiple data storage disks 14 are typicallymounted in vertically spaced and parallel relation on the spindle 16.Rotation of the disk(s) 14 is provided by a spindle motor 18 that iscoupled to the spindle 16 to simultaneously spin the data storagedisk(s) 14 at an appropriate rate.

The disk drive 10 also includes an actuator arm assembly 20 that pivotsabout a pivot bearing 22, which in turn is rotatably supported by thebase plate 12 and/or cover. The actuator arm assembly 20 includes one ormore individual rigid actuator arms 24 that extend out from near thepivot bearing 22. Multiple actuator arms 24 are typically disposed invertically spaced relation, with one actuator arm 24 being provided foreach major data storage surface of each data storage disk 14 of the diskdrive 10. Other types of actuator arm assembly configurations could beutilized as well, such as an “E” block having one or more rigid actuatorarm tips or the like that cantilever from a common structure. In anycase, movement of the actuator arm assembly 20 is provided by anactuator arm drive assembly, such as a voice coil motor 26 or the like.The voice coil motor 26 is a magnetic assembly that controls theoperation of the actuator arm assembly 20 under the direction of controlelectronics 28. Any appropriate actuator arm assembly drive type may beutilized by the disk drive 10, including a linear drive (for the casewhere the actuator arm assembly 20 is interconnected with the base plate12 and/or cover for linear movement versus the illustrated pivotingmovement about the pivot bearing 22) and other types of rotationaldrives.

A load beam or suspension 30 is attached to the free end of eachactuator arm 24 and cantilevers therefrom. Typically, the suspension 30is biased generally toward its corresponding disk 14 by a spring-likeforce. A slider 32 is disposed at or near the free end of eachsuspension 30. What is commonly referred to as the “head” (e.g.,transducer) is appropriately mounted on the slider 32 and is used indisk drive read/write operations.

The head on the slider 32 may utilize various types of read sensortechnologies such as anisotropic magnetoresistive (AMR), giantmagnetoresistive (GMR), tunneling magnetoresistive (TuMR), othermagnetoresistive technologies, or other suitable technologies. AMR isdue to the anisotropic magnetoresistive effect with a normalized changein resistance (ΔR/R) of 2-4%. GMR results from spin-dependent scatteringmechanisms between two (or more) magnetic layers. The typical use inrecording heads is the spin valve device that uses a pinned magneticlayer and a free layer to detect external fields. The normalized changein resistance is typically 8-12%, but can be as large as 15-20% whenused with specular capping layers and spin-filter layers. TuMR issimilar to GMR, but is due to spin dependent tunneling currents acrossan isolation layer. The typical embodiment includes a free layer and apinned layer separated by a insulating layer of Al₂O₃ with the currentflowing perpendicular to the film plane, producing normalized change inresistance of 12-25%. The term magnetoresistive is used in thisapplication to refer to all these types of magnetoresistive sensors andany others in which a variation in resistance of the sensor due to theapplication of an external magnetic field is detected. The writetransducer technology of the head of the present invention is discussedin further detail below.

The biasing forces exerted by the suspension 30 on its correspondingslider 32 thereby attempt to move the slider 32 in the direction of itscorresponding disk 14. Typically, this biasing force is such that if theslider 32 were positioned over its corresponding disk 14, without thedisk 14 being rotated at a sufficient velocity, the slider 32 would bein contact with the disk 14.

The head on the slider 32 is interconnected with the control electronics28 of the disk drive 10 by a flex cable 34 that is typically mounted onthe actuator arm assembly 20. Signals are exchanged between the head andits corresponding data storage disk 14 for disk drive read/writeoperations. In this regard, the voice coil motor 26 is utilized to pivotthe actuator arm assembly 20 to simultaneously move the slider 32 alonga path 36 and “across” the corresponding data storage disk 14 toposition the head at the desired/required radial position on the disk 14(i.e., at the approximate location of the correct track on the datastorage disk 14) for disk drive read/write operations.

When the disk drive 10 is not in operation, the actuator arm assembly 20is pivoted to a “parked position” to dispose each slider 32 generally ator beyond a perimeter of its corresponding data storage disk 14, but inany case in vertically spaced relation to its corresponding disk 14.This is commonly referred to in the art as being a dynamic load/unloaddisk drive configuration. In this regard, the disk drive 10 includes aramp assembly 38 that is disposed beyond a perimeter of the data storagedisk 14 to typically both move the corresponding slider 32 verticallyaway from its corresponding data storage disk 14 and to also exertsomewhat of a retaining force on the actuator arm assembly 20. Anyconfiguration for the ramp assembly 38 that provides the desired“parking” function may be utilized. The disk drive 10 could also beconfigured to be of the contact start/stop type, where the actuator armassembly 20 would pivot in a direction to dispose the slider(s) 32typically toward an inner, non-data storage region of the correspondingdata storage disk 14. Terminating the rotation of the data storagedisk(s) 14 in this type of disk drive configuration would then result inthe slider(s) 32 actually establishing contact with or “landing” on itscorresponding data storage disk 14, and the slider 32 would remain onthe disk 14 until disk drive operations are re-initiated.

The slider 32 of the disk drive 10 may be configured to “fly” on an airbearing during rotation of its corresponding data storage disk(s) 14 ata sufficient velocity. The slider 32 may be disposed at a pitch anglesuch that its leading edge is disposed further from its correspondingdata storage disk 14 than its trailing edge. The head would typically beincorporated on the slider 32 generally toward its trailing edge sincethis is positioned closest to its corresponding disk 14. Other pitchangles/orientations could also be utilized for flying the slider 32.

FIG. 2 illustrates a head 33 that is mounted on the slider 32. The head33 comprises a read head 40 and a write head 50. The read head 40comprises a read sensor 41, and read shields 44 and 45. The write head50 comprises a pole tip 51 connected to a write yoke 56, a write returnyoke 55 connected to the write yoke 56 on one end, and the write returnyoke 55 connected to a write shield (return shield) on a second end.Furthermore, the write head 50 comprises conductive coils 58 surroundingthe write yoke 56 for the generation of a magnetic field. When anelectric current is passed through the conductive coils 58, the currentinduces a magnetic field in the write yoke 56, which causes the pole tip51 to become magnetized. FIG. 2 illustrates the state of the head 33while the disk drive 10 is in operation. During a write or a readoperation, the head 33 is positioned in close proximity to the disk 14,separated by an air-bearing-surface (ABS) 60. The disk 14 comprises asoft underlayer (SUL) 141 supporting a magnetic storage layer 143.

During a write operation of the disk drive, the slider 32 moves to aposition where the head 33 is positioned directly above the region ofthe disk 14 corresponding to a bit of data, where the write head 50 andthe disk 14 is separated by an air-bearing-surface (ABS) 60. A currentflows through the conductive coils 58 of the write head 50 generating amagnetic field in the write yoke 56. The magnetization in the write yoke56 causes the pole tip 51 to become magnetized. The SUL 141 is typicallycomposed of a magnetically soft material with higher magneticpermeability compared to the material of the magnetic storage layer 143.As a result of the higher permeability of the SUL 141, the magnetic flux80 from the pole tip 51 passes vertically through the magnetic storagelayer 143 to the SUL 141. The magnetic flux 80 then passes through theSUL 141 and returns to the write return yoke 55 (return path). Becausethe tip area of the pole tip 51 is small, the magnetic flux 80 densityis high in the region of the magnetic storage layer 143 positionedimmediately under the pole tip 51; hence, the magnetic flux 80 iscapable of causing a change of the storage state of a bit of data. Bycomparison, because the return path is wider in surface area, themagnetic flux density on the return path is lower since it isdistributed over a wide area. Therefore, the storage state of themagnetic storage layer 143 on the return path remains unchanged.

As the pole tip 51 emits the magnetic flux 80 during a write operation,the pole tip 51 also emits magnetic flux onto neighboring tracks (fringefield), which could potentially cause inadvertent erasure on theneighboring tracks, or enhance thermal decay of adjacent tracks.

FIGS. 3-7 illustrates details of the tip region within the dashed ovalarea labeled “Tip Region” of FIG. 2. Each of FIGS. 3( a)-7(a)illustrates a frontal view of the tip region, as viewed from the leftedge of FIG. 2 towards the right edge. Each of FIGS. 3( b)-7(b)illustrates a bottom view, as viewed from the perspective of the ABS 60,or as viewed from the bottom edge of FIG. 2 towards the top edge.

FIG. 3 illustrates the structures of the tip region in a design withoutside shields. FIG. 3( a) is a frontal view of the pole tip 1-51. Thepole tip 1-51 connects to the write yoke 1-56, but is smaller indimension. The write yoke 1-56 narrows down in a trapezoidal-shaped neckregion to connect to the write pole tip 1-51. The height of the pole tip1-51 is called the pole tip neck length (PL). The pole tip 1-51 isseparated from the disk 14 by an air-bearing-surface (ABS) 60. The disk14 comprises a magnetic storage layer 143 supported by a SUL 141, aspreviously discussed in reference to FIG. 2. FIG. 3( b) illustrates abottom view (ABS view). The pole tip 1-51 is closed spaced from thewrite shield (return shield) 1-53, separated by a write pole tip gap(WP).

FIG. 4 illustrates the region around the pole tip in a design with sideshields 2-59 connected to the write shield 2-53. FIG. 4( a) is a frontalview of the pole tip 2-51. On both the left and right sides of the poletip 2-51, two side shields 2-59 are disposed in close proximity to thepole tip 2-51, each separated by a side shield to pole tip gap (SG)distance. FIG. 4( b) illustrates the bottom (ABS) view of FIG. 4( a). Asshown in FIG. 4( b), the side shields 2-59 extends from and areconnected to the write shield 2-53.

In a manufacturing process, the pole tip 2-51 and write shield 2-53 aremanufactured in two separate steps. Since the side shields 2-59 andwrite shield 2-53 are connected as one structure, they must bemanufactured together. Therefore, the manufacturing of the structureshown in FIG. 4 is extremely difficult because the SG dimension (sideshield to pole tip gap) is difficult to control when the side shields2-59 and pole tip 2-51 are manufactured in separate process steps.

Furthermore, as shown in FIG. 4( b), the side shields 2-59 and writeshield 2-53 are connected together throughout the width of the sideshields 2-59, hence they are coupled together magnetically and havesubstantially the same magnetic potential. Because the side shields 2-59are disposed in close proximity to the pole tip 2-51, and havesubstantially similar magnetic potential as the write shield 2-53, it islikely that magnetic flux from the pole tip 2-51 would be leaked to theside shields 2-59 in the design shown in FIG. 4. This decreases theefficiency of the write head 50.

FIG. 5 illustrates one embodiment of the invention where the sideshields 3-59 are “floating” and not connected to the write shield 3-53.FIG. 5( a) illustrates a frontal view and FIG. 5( b) illustrates an ABSview. Each side shield 3-59 has a height of SH, and is separated fromthe pole tip 3-51 by a gap distance of SG. As illustrated in FIG. 5( b),each side shields 3-59 also has a width of SW that is less than theoverall width of the write shield 3-53. Each side shield 3-59 is alsoseparated from the write shield 3-53 by the same gap distance as thepole tip to write shield gap (WG).

The embodiment illustrated in FIG. 5 has the advantage that since theside shields 3-59 are not connected to the write shield 3-53, the sideshields 3-59 can be manufactured in the same process step and defined bythe same photolithography mask as the pole tip 3-51. Since the sideshields 3-59 and the pole tip 3-51 are defined in the same mask step,the gap distance (SG) between the side shields 3-59 and the pole tip3-51 can be controlled precisely.

Furthermore, the embodiment illustrated in FIG. 5 has the advantage thatthe magnetic potential of the side shields 3-59 can be controlled byadjusting the dimensions of the side shields (SH and SW), the gapdistances SG and WG. When the write head 50 is performing a writeoperation, the pole tip 3-51 becomes highly magnetized and hence has ahigh magnetic potential. The write shield 3-53 has a low magneticpotential (close to 0). As previously discussed, when the side shields3-59 have a lower magnetic potential than the pole tip 3-51, some amountof magnetic flux will be leaked from the pole tip 3-51 to the sideshields 3-53. The amount of magnetic flux leakage is directlyproportional to the magnetic potential difference between the pole tip3-51 and the side shields 3-53. Therefore, it is desirable to have theside shields 3-59 with a magnetic potential at a higher level than thatof the write shield 3-53 and relatively close to the potential of thepole tip 3-51 to minimize the amount of magnetic flux leakage whilestill protecting adjacent tracks from fringe field effects. However, itis desirable that an induced field in the magnetic storage layer 143 dueto the magnetic potential of the side shields 3-59 not exceed thenucleation field of the magnetic storage layer 143. Otherwise, the sideshields 3-59 would cause undesired erasures on adjacent tracks.Therefore, an optimum magnetic potential for the side shields 3-59 is amagnetic potential higher than that of the write shield 3-53 and thatinduces a field in the magnetic storage layer 143 close to but lowerthan the nucleation field of the magnetic storage layer 143.

In the embodiment illustrated in FIG. 5, since the side shields 3-59 are“floating” and not directly coupled to any structure with apredetermined magnetic potential, the magnetic potential of the sideshields 3-59 are influenced by the magnetic potentials of nearbystructures. The magnetic potential of each side shield 3-59 isproportional to the magnetic potential of a nearby structure,proportional to the surface area of the side shield 3-59 facing thatnearby structure, and inversely proportional to the gap distance betweenthe side shield 3-59 and that nearby structure. Therefore, for example,if it is more desirable to have the side shields 3-59 have a magneticpotential closer to the write shield 3-53 (which has a magneticpotential close to 0), the area of the side shields 3-59 facing thewrite shield 3-53 can be increased by increasing the width of the sideshields (SW). On the other hand, if it is more desirable to increase themagnetic potential of the side shields 3-59, the area of the sideshields 3-59 facing the pole tip 3-51 can be increased by increasing theside shield height (SH), or decreasing the gap (SG) between the sideshields and the pole tip 3-51.

By a method of finite element analysis or SPICE simulation (in which themagnetic impedances of the gaps are simulated as resistances), it ispossible to design the dimensions of the side shields 3-59 illustratedin FIG. 5 such that the magnetic potential of the side shields 3-59 isany desired value above 0 and below the magnetic potential of the poletip 3-51. In some embodiments of the present invention, the desiredvalue can be set at an optimum magnetic potential just below thenucleation field of the magnetic storage layer 143.

Since the magnetic flux leakage from the pole tip 3-51 to the sideshields 3-59 is proportional to their magnetic potential difference, itis therefore also possible to adjust the dimensions of the side shields3-59 and the gap distances (WG and SG) such that the magnetic fluxleakage is less than 20%.

In some embodiments, the width of the pole tip 3-51 is approximately 80%of the track pitch (track-to-track distance on the disk 14). The sideshield to pole tip gap (SG) is approximately 10-40% of the track pitchto protect fringe field effects on neighboring tracks. The side shieldto pole tip gap (SG) should also be larger than 50% of the pole tip 3-51to SUL 141 distance, to ensure that the magnetic flux emitted from thepole tip 3-51 goes to the SUL 141 rather than the side shields 3-59.Within these dimensional constraints, it is possible to adjust theheight (SH) and width (SW) of the side shields 3-59 to achieve thedesired magnetic potential for the side shields to be at a level nearthe optimum level.

FIG. 6 illustrates another embodiment of the present inventioncomprising a magnetic connector 4-52 connecting each side shield 4-53 tothe write shield 4-53. FIG. 6( a) illustrates a frontal view and FIG. 6(b) illustrates a bottom (ABS) view. The cross-sectional width of eachmagnetic connector 4-52 is less than the width of the side shield (SW)to which it is connected. In this embodiment, since the magneticconnection area between each side shield 4-53 and the write shield 4-53is relatively small, the magnetic coupling between the side shields 4-53and the write shield 4-53 is relatively weak. Since each side shield4-53 is disposed in close proximity to the pole tip 4-51, the magneticpotential of each side shield will be a value above the magneticpotential of the write shield but below the magnetic potential of thepole tip 4-51. Thus, in this embodiment, the magnetic potential of theside shields 4-59 can be adjusted by adjusting the cross-sectional widthof the magnetic connectors 4-52, which determines the amount of magneticcoupling between the side shields 4-52 and the write shield 4-53.

In some embodiments, each magnetic connector 4-52 is composed of amagnetic thin film. In some embodiments, each magnetic connector 4-52 isa magnetic via.

FIG. 7 illustrates yet another embodiment of the present invention. FIG.7( a) illustrates a frontal view and FIG. 7( b) illustrates a bottom(ABS) view. In this embodiment, the width (SW) of each side shield 5-59is made relatively small. However, the height of each side shield 5-59is made longer than the pole tip neck length (PL). In this embodiment,the magnetic coupling between the side shields 5-59 and the write shield5-53 is small since only a small amount of surface area of each sideshield 5-59 directly faces the write shield 5-53. However, there is alarge amount of magnetic coupling between the side shields 5-59 and thepole-tip/yoke structure (elements 5-56 and 5-51) due to the large amountof side shield 3-59 surface area facing it. In this embodiment, themagnetic potential of the side shields can be maintained at a relativelyhigh value.

FIGS. 8-11 illustrate methods of manufacturing a write pole tip withfloating side shields according to various embodiments of the presentinvention. FIGS. 8-10 illustrate various manufacturing methods for thestructure of the pole tip, while FIG. 11 illustrate the overallstructure of the pole tip region.

FIG. 8 illustrates one conventional method of manufacturing the pole tip6-51 and side shields 6-59. A layer of seeding layer 6-71 is firstdeposited on a non-magnetic spacer layer 6-70. Various other structuresfor the head 33 are positioned below the non-magnetic spacer layer 6-70,some of which will be discussed later in reference to FIG. 11. After thedeposition of the seeding layer 6-71, the side shields 6-59 and pole tip6-51 are plated onto the seeding layer 6-71. The region where the sideshields 6-59 and pole tip 6-51 are plated is defined by aphotolithography mask (not shown). The seeding layer 6-71 outside of theregion where the side shields 6-59 and pole tip 6-51 are deposited isthen removed. As previously discussed, because the side shields 6-59 andthe pole tip 6-51 are defined using the same photolithography mask, thisenables precise control of the dimensions of the side shields 6-59 aswell as the gap distance between the side shields 6-59 and pole tip6-51.

In one specific embodiment, the spacer layer 6-70 is composed of Al₂O₃,the side shields 6-59 and pole tip 6-59 are composed of NiFe, and theseeding layer 6-71 is a copper layer. However, in other embodiments,various other suitable materials can be used. For example, the seedinglayer 6-71 could be composed of a Copper-Tin alloy or a Copper-Zincalloy.

As shown in FIG. 8( b), after the formation of the side shields 6-59 andpole tip 6-51, a non-magnetic encapsulation layer is deposited onto thestructure using a sputter deposition process. A sputter depositionprocess is a relatively fast process where a thick layer can bedeposited in a relatively short period of time. However, due to the highaspect ratio (depth/width) of the trench between each side shield 6-59and the pole tip 6-51, a sputter deposition may not be able tocompletely fill these trenches. As illustrated in FIG. 8( b), voids 6-74could potentially form on the bottom of the trenches. The likelihood ofthe formation of the voids 6-74 depends on the sputter depositionprocess as well as the aspect ratio of the trenches between each sideshield 6-59 and pole tip 6-51. However, the formation of voids 6-74 ishighly undesirable because it could lead to reliability degradation andfailures.

FIG. 9 illustrates a method to manufacture the pole tip structureeliminating the formation of voids according to one embodiment of thepresent invention. The process steps that are identical to the processdiscussed while referring to FIG. 8 is omitted here. As shown in FIG. 9(a), after the plating of the side shields 7-59 and pole tip 7-51, thestructure is subject to a normal incident ion-beam deposition process ofa non-magnetic material, such as Al₂O₃. Since the incident angle of theion-beam deposition process is normal (90 degrees) to the substrate, thetrenches between each side shield 7-59 and pole tip 7-51 is filled withthe non-magnetic material without the risk of void formation.

As illustrated in FIG. 9( b), the non-magnetic layer 7-76 is depositedat a normal angle over the entire structure, including on top of theside shields 7-59 and pole tip 7-51. The structure is then subjected toa chemical-mechanical polishing step for planarization, resulting in astructure shown in FIG. 9( c).

As compared to the method described in FIG. 8, the current method hasthe advantage that it eliminates the risk of void-formation on thebottom of the trenches between the side shields 7-59 and pole tip 7-51.However, the ion-beam deposition process is a slower process compared tothe sputtering process. It takes a relatively long time to form thethick non-magnetic layer 7-76 using ion-beam deposition as required bythis method. Hence, the current method increases processing time andpossibly the processing cost compared to the method described in FIG. 8.

FIG. 10 illustrates a method according to another embodiment of thepresent invention where the formation of voids can be avoided withoutthe need for a lengthy ion-beam deposition process. As shown in FIG. 10(a), after the formation of the side shields 7-59 and pole tip 7-51, theseeding layer 8-71 is not removed and remains even in the exposedregions. The structure is then subjected to an angled incident ion-beamassisted deposition of a non-magnetic material, such as Al₂O₃, for ashort period of time. In this embodiment, the angle is set at +/−20°from the normal angle. However, in other embodiments, other angles whichmeets the objective of the present invention can also be used.

As shown in FIG. 10( b), a thin layer of non-magnetic material 8-76 canbe quickly formed over the structure through the angled-incidention-beam assisted deposition. However, because the ion-beam assisteddeposition is at an angle, the bottom of the trenches between the sideshields 7-59 and pole tip 7-51 is not covered by the non-magnetic layer8-76 because the angled ion beams are blocked by nearby structures.Hence, the seeding layer 8-71 on the bottom of the trenches between theside shields 7-59 and pole tip 7-51 remain exposed.

In various embodiments, due to scattering effects of angled ion-beamdeposition, a very thin layer of magnetic material 8-76 may also beformed on the bottom of the trenches between the side shields 7-59 andpole tip 7-51. Such a problem can be resolved by subjecting thestructure to a light ion-beam milling process, with the ion beam at anormal incident angle to the substrate. Because the layer on the bottomof the trenches is much thinner than in other regions, the seeding layer8-71 on the bottom of the trenches can be exposed without exposing otherregions of the seeding layer 8-71.

As shown in FIG. 10( c), the structure is then subject to aelectro-plating process of a non-magnetic material. Since only theregions of the seeding layer 8-71 on the bottom of the trenches betweenthe side shields 7-59 and pole tip 7-51 are exposed, only the trenches8-78 will be filled by the electro-plating process. The material fillingthe trenches 8-78 must be a non-magnetic material, such as Ni—P alloy(with P>80%), a Copper-Zinc alloy, or a Copper-Tin alloy.

After the trenches 8-78 are filled with a non-magnetic material, thestructure is then subject to a sputtering deposition of a non-magneticlayer 8-72, such as Al₂O₃. FIG. 10( d) illustrates the profile of thestructure after the deposition of the non-magnetic layer 8-72. Thestructure is then subject to a chemical-mechanical polishing step forplanarization. FIG. 10( e) illustrates the profile of the structureafter the chemical-mechanical polishing step.

In this embodiment, there is an advantage that only a short ion-beamassisted deposition is required. Hence, as compared to the methoddescribed while referring to FIG. 9, the process time and expense arereduced. However, because the trenches between the side shields 7-59 andpole tip 7-51 are filled using a plating process, the risk ofvoid-formation is also eliminated.

FIG. 11 illustrates the main processing steps of the layers surroundingthe tip region according to an embodiment of the present invention. Thisdiscussion focuses on the main process steps relevant to the presentinvention, and certain conventional steps such as the formation of seedlayers, certain photolithography layers, chemical-mechanical polishing,layers for electrical connections, and other process steps are omitted.The perspective of FIG. 11 is rotated 90 degrees from the perspectiveshown in FIGS. 8-10, viewing the structures in FIGS. 8-10 from the rightedge of the figure towards the left edge. FIG. 11 only illustrates theregion near the pole tip, and other structures that are commonly foundin a head 33 is omitted. The structure is formed on a substrate (notshown). Typically, the read head 40 is formed in the space between thenon-magnetic spacer layer 70 and the underlying substrate (not shown).The left edge of FIG. 11 illustrates the bottom edge of the write head50 as shown in FIG. 5. The space beyond the left edge of FIG. 11 is theair-bearing-surface (ABS) 60.

As shown in FIG. 11, a non-magnetic spacer layer 70 is deposited,encasing a set of conductive coils 58. The coils 58 can be a pan-caketype coil (wrapping horizontally with respect to FIG. 11) or asolenoidal-type coil (wrapping vertically with respect to FIG. 11).Next, the pole tip layer 51 and side shields 59 are deposited on thenon-magnetic spacer layer 70.

The formation of the pole tip 51 and side shields 59 are accomplishedusing one of the methods discussed in detail while referring to FIG. 8,9, or 10. In FIG. 11, the side shield 59 is obscuring the view of thebottom of the pole tip 51. It is noted that both the side shield 59 andpole tip 51 extends to the left edge of FIG. 11. There is another sideshield 59 (not shown) behind the pole tip layer 51, obscured by both thefirst side shield 59 and pole tip layer 51.

Next, a thick write yoke layer 56 is deposited over the entire pole tiplayer 51 except the region near the tip. The write yoke layer 56increases the thickness and magnetic flux conductance of the pole tiplayer 51. After the deposition of the write yoke layer 56, anothernon-magnetic spacer layer 82 composing Al₂O₃ is deposited. The thicknessof this non-magnetic spacer layer 82 determines the gap distance (WG)between the pole tip 51 and the write shield 53. On top of non-magneticspacer layer 82, a non-magnetic ramp 84 is deposited, covering theregion above the write yoke layer 58 and ramping down towards the poletip (left edge of the figure). The non-magnetic ramp 84 is composed ofhard-baked photoresist, and encases a second set of coils 58. Together,the non-magnetic spacer layer 82 and the non-magnetic ramp 84 separatesthe pole tip 51 and write yoke 56 from the write shield 53. Next, athick layer of magnetic material is deposited over the entire structure,forming the write shield 53 and write return yoke 55. It is noted thatthe write yoke 56 ultimately connects to the write return yoke 55, inthe region beyond the right edge of FIG. 11 (not shown). (See FIG. 2).

In various embodiments, each side shield 59 is separated from the writeshield 53 by a non-magnetic material. In various alternate embodiments,each side shield 59 is separated from the write shield 53 by a magneticmaterial having low saturation magnetization or low permeability. Also,in various alternate embodiments, each side shield 59 is separated fromthe write shield 53 by a magnetic material having low saturationmagnetization or low permeability such that, during a write operation, adrop of magnetic potential from the write shield 53 to each side shield59 is at least 25% of a potential difference from the write shield 53 toa SUL of an adjacent magnetic recording medium.

In various embodiments, each side shield 59 is separated from the poletip 51 by a non-magnetic material. In various alternate embodiments,each side shield 59 is separated from the pole tip 51 by a magneticmaterial having low saturation magnetization or low permeability. Also,in various alternate embodiments, each side shield 59 is separated fromthe pole tip 51 by a magnetic material having low saturationmagnetization or low permeability and each side shield 59 is separatedfrom the write shield 53 by a magnetic material having low saturationmagnetization or low permeability. For various such alternateembodiments, low saturation magnetization and low permeability limitsfor a suitable magnetic material to separate each side shield 59 fromthe pole tip 51 may be different than low saturation magnetization andlow permeability limits for a suitable particular magnetic material toseparate each side shield 59 from the write shield 53.

The embodiments disclosed herein are to be considered in all respects asillustrative, and not restrictive of the invention. The presentinvention is in no way limited to the embodiments described above.Various modifications and changes may be made to the embodiments withoutdeparting from the spirit and scope of the invention. The scope of theinvention is indicated by the attached claims, rather than theembodiments. Various modifications and changes that come within themeaning and range of equivalency of the claims are intended to be withinthe scope of the invention.

1. A write head for a disk drive, the write head suitable forperpendicularly recording data in an adjacent magnetic recording medium,the magnetic recording medium comprising a magnetic recording layer on asoft underlayer (SUL), the write head comprising: a pole tip; a writeyoke connected to the pole tip; a write return yoke, wherein the writeyoke connects to a first end of the write return yoke; a write shieldconnected to a second end of the write return yoke different from thefirst end; one or more electrically conductive coils surrounding thewrite yoke; and one or more side shields disposed in close proximity tothe pole tip; wherein each of the one or more side shields is separatedfrom the pole tip by a non-magnetic material or by a magnetic materialwith low saturation magnetization or by a magnetic material with lowpermeability; and wherein each of the one or more side shields isseparated from the write shield by a particular non-magnetic material orby a particular magnetic material with low saturation magnetization orby a particular magnetic material with low permeability; and wherein theone or more side shields are dimensioned and spaced such that each ofthe one or more side shields has a magnetic potential higher than themagnetic potential of the write shield but an induced field in themagnetic recording layer from each of the one or more side shields islower than a nucleation field of the magnetic recording layer during awrite operation.
 2. The write head of claim 1, wherein each of the oneor more side shields is separated from the pole tip by the non-magneticmaterial; and wherein each of the one or more side shields is separatedfrom the write shield by the particular non-magnetic material.
 3. Thewrite head of claim 2, wherein the particular non-magnetic material is asame material as the non-magnetic material.
 4. The write head of claim1, wherein the one or more side shields comprise two side shieldsdisposed in parallel to the write shield on opposite sides of the poletip.
 5. The write head of claim 1, wherein each of the one or more sideshields is encased in a specific non-magnetic material.
 6. The writehead of claim 1, wherein each of the one or more side shields isseparated from the write shield by the particular magnetic material withlow saturation magnetization or by the particular magnetic material withlow permeability; and wherein, during a write operation by the writehead, a drop of magnetic potential from the write shield to each of theone or more side shields is at least 25% of a potential difference fromthe write shield to the SUL.
 7. The write head of claim 1, wherein aheight of each of the one or more side shields in a directionsubstantially parallel to the pole tip is longer than a neck length ofthe pole tip.
 8. The write head of claim 1, wherein a gap distancebetween the pole tip and each of the one or more side shields is between10% to 40% of a track pitch of the magnetic recording layer, and whereinsaid gap distance is also larger than 50% of a pole tip to softunderlayer (SUL) distance during a write operation.
 9. The write head ofclaim 1, wherein the one or more side shields are dimensioned and spacedsuch that during a write operation, a magnetic flux leakage from thepole tip to the one or more side shields is less than 20% of a totalmagnetic flux of the pole tip.
 10. The write head of claim 1, furthercomprising one or more magnetic connectors connecting each of the one ormore side shields to the write shield, wherein a total cross-sectionalwidth of the one or more magnetic connectors is less than a total widthof the one or more side shields, said width of the one or more sideshields measured along a direction substantially parallel to the writeshield.
 11. The write head of claim 10, wherein a the magnetic potentialof the first or more side shields can be adjusted by adjusting across-sectional width of each of the one or more magnetic connectors.12. A disk drive device, comprising: one or more recording media, eachrecording medium of the one or more recording media comprising a softunderlayer (SUL) supporting a magnetic recording layer; and one or moremagnetic heads, each of the one or more magnetic heads supported forperpendicular recording on a corresponding recording medium of the oneor more recording media; wherein each magnetic head of the one or moremagnetic heads, comprises: a pole tip; a write yoke connected to thepole tip; a write return yoke, wherein the write yoke connects to afirst end of the write return yoke; a write shield connected to a secondend of the write return yoke different from the first end; one or moreelectrically conductive coils surrounding the write yoke; and one ormore side shields disposed in close proximity to the pole tip; whereineach of the one or more side shields is separated from the pole tip by anon-magnetic material or by a magnetic material with low saturationmagnetization or by a magnetic material with low permeability; andwherein each of the one or more side shields is separated from the writeshield by a particular non-magnetic material or by a particular magneticmaterial with low saturation magnetization or by a particular magneticmaterial with low permeability; and wherein the one or more side shieldsare dimensioned and spaced such that each of the one or more sideshields has a magnetic potential higher than a magnetic potential of thewrite shield but an induced field in a corresponding recording medium ofthe one or more recording media from each of the one or more sideshields is lower than a nucleation field of the magnetic recording layerof the corresponding recording medium during a write operation.
 13. Thedisk drive device according to claim 12, wherein each of the one or moreside shields is separated from the pole tip by the non-magnetic materialin each of the one or more magnetic heads; and wherein each of the oneor more side shields is separated from the write shield by theparticular non-magnetic material in each of the one or more magneticheads.
 14. The disk drive device according to claim 13, wherein theparticular non-magnetic material is a same material as the non-magneticmaterial.
 15. The disk drive device according to claim 12, wherein eachof the one or more side shields is separated from the write shield bythe particular magnetic material with low saturation magnetization or bythe particular magnetic material with low permeability in each of theone or more magnetic heads; and wherein, during a write operation of aparticular magnetic head of the one or more magnetic heads, a drop ofmagnetic potential from the write shield of the particular magnetic headto each of the one or more side shields of the particular magnetic headis at least 25% of a potential difference from the write shield of theparticular magnetic head to the SUL of the corresponding recordingmedium.
 16. The disk drive device according to claim 12, wherein the oneor more side shields comprise two side shields disposed in parallel tothe write shield on opposite sides of the pole tip.
 17. The disk drivedevice according to claim 12, wherein each of the one or more sideshields is encased in a specific non-magnetic material.
 18. The diskdrive device according to claim 12, further comprising one or moremagnetic connectors connecting each of the one or more side shields tothe write shield, wherein a total cross-sectional width of the one ormore magnetic connectors is less than a total width of the one or moreside shields, said width of the one or more side shields measured alonga direction substantially parallel to the write shield.
 19. A write headfor a disk drive, the write head suitable for perpendicularly recordingdata in an adjacent magnetic recording medium, the magnetic recordingmedium comprising a magnetic recording layer on a soft underlayer (SUL),the write head comprising: a pole tip; a write yoke connected to thepole tip; a write return yoke, wherein the write yoke connects to afirst end of the write return yoke; a write shield connected to a secondend of the write return yoke different from the first end; one or moreelectrically conductive coils surrounding the write yoke; and one ormore side shields disposed in close proximity to the pole tip; whereineach of the one or more side shields is separated from the pole tip by anon-magnetic material or by a magnetic material with low saturationmagnetization or by a magnetic material with low permeability; andwherein each of the one or more side shields is separated from the writeshield by a particular non-magnetic material or by a particular magneticmaterial with low saturation magnetization or by a particular magneticmaterial with low permeability; and wherein the one or more side shieldsare dimensioned and spaced such that during a write operation, amagnetic flux leakage from the pole tip to the one or more side shieldsis less than 20% of a total magnetic flux of the pole tip.
 20. The writehead of claim 19, wherein a magnetic potential of each of the one ormore side shields is higher than the magnetic potential of the writeshield during a write operation.
 21. The write head of claim 19, whereineach of the one or more side shields is separated from the write shieldby the particular magnetic material with low saturation magnetization orby the particular magnetic material with low permeability; and wherein,during a write operation by the write head, a drop of magnetic potentialfrom the write shield to each of the one or more side shields is atleast 25% of a potential difference from the write shield to the SUL.22. The write head of claim 19, wherein the one or more side shields aredimensioned and spaced such that each of the one or more side shieldshas a magnetic potential higher than the magnetic potential of the writeshield but an induced field in the magnetic recording layer from each ofthe one or more side shields is lower than a nucleation field of themagnetic recording layer during a write operation.
 23. The write head ofclaim 19, wherein a gap distance between the pole tip and each of theone or more side shields is between 10% to 40% of a track pitch of themagnetic recording layer, and wherein said gap distance is also largerthan 50% of a pole tip to soft underlayer (SUL) distance during a writeoperation.
 24. The write head of claim 19, wherein each of the one ormore side shields is separated from the pole tip by the non-magneticmaterial; and wherein each of the one or more side shields is separatedfrom the write shield by the particular non-magnetic material.